Field of the Invention
The 2:1 layered silicates, mica, and vermiculite are processed into a variety of forms and are used in many different products. Their fire resistance especially makes them desirable for use in many products. They have, for example, been used in fire resistant boards, papers, and coatings.
These 2:1 layered silicates (mica and vermiculite) have, of course, been used in their natural state (for example as fillers). Many different types of compositions can be obtained from these silicates. They have been chemically delaminated to separate the platelets (lamellae) and produce mineral compositions that can form aqueous suspensions or dispersions.
The chemically delaminated micas and vermiculites have been subjected to ion exchange to get silicate flocs. Vermiculite has been heat exfoliated to convert the water of hydration into steam, expand the vermiculite, and produce exfoliated vermiculite. Although the exfoliated vermiculite is good as an insulation, the pore structure is open and very irregular, with many layers remaining tightly knitted together and others widely separated by distances of 1,000 microns and more.
The present invention provides and describes a new and different compositional form of 2:1 layered silicates. The 2:1 layered silicate compositions described herein are low in density, highly microporous with a regular pore structure, and have thermal conductivity properties that are both unusual and desirable. Advantageously, instant compositions can be made into a variety of structures that can provide thermal insulation and a level of heat protection which, heretofore, has not been possible with the 2:1 layered silicates.
Different methods for the preparation of these silicate compositions are also described herein.